Pumping diaphragm and pump assembly



J u ne 15 1965 w, HARRY ETAL 3,188,970

PUMPING DIAPHRAGM AND PUMP ASSEMBLY Filed Sept. 11, 1962- INVENTORS 'a/ab/z 1/ Har y, 6; BY [MY/1rd .7/7/5'156/ A ORNEY United States Patent 3,188,970 PUMPING DIAPHRAGM AND PUMP ASSEMBLY Gordon W. Harry, Flushing, and Willard T. Nickel, Flint, Mich., assignors to General Motors Corporation, Detroit, Mich., a corporation of Delaware Filed Sept. 11, 1962, Ser. No. 222,874 8 Claims. (Cl. 103-450) This invention relates to diaphragms and pumps including such diaphragms and more particularly to pumping diaphragms and pump assemblies suitable for handling fluids such as air or liquid fuel.

In conventional diaphragm pumps there is a tendency for the diaphragms working portion to yield under fluid pressure and thereby make the pumping stroke less effective. Also, undue fiexure and possible reversal of a bight in a diaphragm increases the stress placed upon the diaphragm material with consequent loss in the useful service life of the diaphragm and the situation is rendered more diflicult when a given pump is of the double action type.

An object of the present invention is to provide an improved pump assembly in which a diaphragm is used having the ability to effect maximum pump displacement with minimum wear due to flexure. Another object is to provide an improved diaphragm which may be firmly retained by the actuating mechanism and also which will effectively resist distortion by fluid pressure thereby to gain a maximum pump displacement.

To these ends, a feature of the present invention is a pump assembly having a pumping diaphragm including two marginal membranes, an outer toroid interposed be tween the membranes, and an inner toroid retained by backing plates. Another feature is a flexible pumping diaphragm having inner and outer toroids and also marginal membranes enclosing the outer toroid. Another feature is a flexible pumping diaphragm in which one toroid cooperates with two marginal membranes in defining an annular recess for receiving a fluid.

These and other important features of the invention will now be described in detail in the specification and then pointed out more particularly in the appended claims.

In the drawings:

FIGURE 1 is a cross-sectional view of a double acting air pump assembly constituting one embodiment of the present invention, the view being taken along the line 11 of FIGURE 2;

FIGURE 2 is a partial plan view of the pump shown in FIGURE 1 with portions broken away better to illustrate the construction; and

FIGURE 3 is a perspective view of the diaphragm used in the structure of FIGURES 1 and 2 with a portion broken away.

The pump is illustrated as having a casing made up of two parts and 12 held together by means of bolts 14 with two membranes 16 and 18 of a pumping diaphragm 20 interposed.

The upper part 10 defines an inlet passage 22 and an outlet passage 24. These are served by a conventional pump one-way inlet valve 26 and a conventional one-way outlet valve 28 respectively. The lower half 12 of the casing is provided with an inlet passage 30 and an outlet passage 32 as served by an inlet valve 34 and an outlet valve 36 respectively. The passages 30 and 32 are blocked olf by means of plates 38 and 40 whereas the passages 22 and 24 are fitted with nipples or connections 42 and 44 respectively.

The casing halves 10 and 12 are provided with registering pairs of passages 46, 48 and 50, 52 so that the inlet passages 22 and 30 are in communication and the outlet passages 24 and 32 are in communication. The membranes 16 and 18 are apertured as at 54 and 56 permitting this communication. The membranes are also apertured at 53 at spaced intervals around their margins for the accommodation of the bolts 14.

The lower half 12 of the casing is formed with a bore or cylinder 60 in which a cylindrical sleeve 62 is adapted to slide. The upper end of the bore 60 is enlarged as at 64 fixedly to retain a guide disk 66. This disk is provided with an opening through which a plunger 68 may slide up and down without undue leakage. The lower end of the plunger is fixed by means of a pin 70 to the sleeve 62 for movement with the latter and pivotally mounted on the pin 70 is the upper end of a connecting rod 72. The lower end of the latter is journaled on a crank 74 which is pictured in FIGURE 1 in its lowest rotative position. A cover 76 is attached to the casing half 12 to enclose the crank arrangement.

The plunger 68 is provided with a reduced upper end portion 77 and this portion is threaded to receive a nut 78 and a washer 80. The nut and washer serve to retain two backing plates 82 and 84, these having rounded edges as at 86 and 88 respectively. The marginal portions of the plates 82 and 84 bear facing annular recesses snugly to receive an inner annulus of the diaphragm 20. The diaphragm also is provided with an outer annulus 92 interposed between the membranes 16 and 18. The plates 82 and 84 firmly hold the diaphragm by means of its inner annulus 90 and the rounded edges 86 and 88 of the plates firmly back up the outer surfaces of the diaphragm as seen clearly in FIGURE 1.

It will be noted in FIGURE 3 that, prior to pump assembly, the membranes 16 and 13 are in planes parallel with a plane in which the inner and outer annuli 90 and 92 lie, but in the assembly of the pump the membranes 16 and 18 are clamped together by the casing halves and cooperate with the outer annulus 92 in defining an annular space 100. This space is filled with a liquid such as lubricating oil during pump assembly.

In operating th pump illustrated in the drawings, air is admitted through the connection 42 to the inner chambers 22 and 30. This air is alternately admitted by the inlet valves 26 and 34 to the pumping chambers A and B on opposite sides of the diaphragm 20 as the plunger 68 is reciprocated by the crank 74 and connecting rod 72. During the exhaust strokes the air is alternately discharged through the exhaust valves 28 and 36 by way of the nipple 44.

Due to the peculiar structure of the diaphragm 20, the latter cannot pull out from between the backing plates 82 and 84 and during the pumping cycle and particularly at each end of a pumping stroke the outer annulus 92 cooperates in maintaining the diaphragm in such a shape as to insure the maximum pump displacement. The liquid contained within the annular chamber cooperates with the outer annulus 92 in this function and, although the use of such liquid is not essential in practicing the present invention it is preferable.

We claim:

1. A pump assembly comprising a casing, pumping structure within said casing and including a flexible diaphragm having marginal membranes enclosing an annular space and cooperating with said casing in defining a pumping chamber, inner and outer toroids constituting parts of said diaphragm, backing plates engaging opposite sides of said diaphragm with said inner toroid interposed, said outer toroid being interposed between said membranes partially to define said annular space and surrounding the peripheries of said backing plates, and said outer toroid being spaced from the wall of said casing.

2. A pump assembly comprising a casing, pumping structure within said casing and including a flexible diaphragm having marginal membranes enclosing an annular space and cooperating with said casing in defining at least one pumping chamber, inner and outer toroids constituting parts of said diaphragm, said posite sides of said diaphragm and engaging said inner toroid within the inner peripheries of said membranes, and said outer toroid being interposed between said membranesand spaced from the Wall ofsaid casing.

3. A pump assembly comprising a casing, pumping structure within said casing and including a flexible diaphragm having marginal membranes cooperating With said casing in defining at least one pumping chamber, inner and outer toroids constituting parts of said diaphragm, backing plates engaging oppositetsides ofsaid diaphragm,

marginal portions of :said backing plates being effective to clamp said inner toroid 'between them and the edges of said plates being rounded in areas contacting said diaphragm, and an annular surface portion of said outer toroidbeing spaced from thesaid marginal membranes.

4. A flexible diaphragm having spaced marginal membranes when free and a toroid interposed between and integral with said membranes, 1 it 5. A flexible diaphragm having one inner tonoid and one outer toroid in one plane and two marginal membranes extending from said outer toroid in planes parallel with said first plane. Y

6. A flexible diaphrag membranes and toroids being integrah V v 7. A pump'assembly comprising a casing, a pumping structure within said casing and-including a flexible diaphragm having marginal membranes enclosing an annular m as set forth in cla inner toroid being integral with said membranes, backing plates engaging opim 5, said a r ,4 a

space and cooperating with a wall of said casing in defining' a pumping chamber on each side-of said diaphragm,

, inner and outer toroids constituting integral and adjacent parts of said'diaphragm, backing plates engaging opposite sides of said diaphragm and said inner toroid, said outer toroid being interposed between said membranes and closely surrounding the peripheries of said backing plates, edges of-said plates having curved areas in contact with the diaphragm, and s'aidoutertoroid being spaced from the said wall of said casing. v

8. A pumping assembly comprising a casing, a pumping structure 'within said casing and including a flexible diaphragm having marginal membranes cooperating with said a. casing in defining at least one pumping chamber, a toroid interposed between" said membranes' and cooperating with the latter in defining an annular chamber, liquid fillingsaidannular chamber, backing plates engaging said toroid for actuating said membranes, and said toroid being spaced from said casing.

' ReEerences Cite'd by the Examiner V UNITEDISTATES PATENTS 356,997 2/87 Gil 103-151 X 5 1 2,751,850 6/56 Hoover "103-450 2,774,380 12/56' Hudson 10315() X 2,931,311 4/60 Ulm et a1. 103150 V LAURENCE ViEFNER,PrimaryExaminer. 

1. A PUMP ASSEMBLY COMPRISING A CASING, PUMPING STRUCTURE WITHIN SAID CASING AND INCLUDING A FLEXIBLE DIAPHRAGM HAVING MARGINAL MEMBRANES ENCLOSING AN ANNULAR SPACE AND COOPERATING WITH SAID CASING IN DEFINING A PUMPING CHAMBER, INNER AND OUTER TOROIDS CONSTITUTING PARTS OF SAID DIAPHRAGM, BACKING PLATES ENGAGING OPPOSITE SIDES OF SAID DIAPHRAGM WITH SAID INNER TOROID INTERPOSED, SAID OUTER TOROID BEING INTERPOSED BETWEN SAID MEMBRANES PARTIALLY TO DEFINE SAID ANNULAR SPACE AND SURROUNDING THE PERIPHERIES OF SAID BACKING PLATES, AND SAID OUTER TOROID BEING SPACED FROM THE WALL OF SAID CASING. 